|
| 1 | +'use strict'; |
| 2 | + |
| 3 | +class AsyncEventEmitter { |
| 4 | + constructor() { |
| 5 | + this.events = new Map(); |
| 6 | + this.wrappers = new Map(); |
| 7 | + } |
| 8 | + |
| 9 | + on(name, fn) { |
| 10 | + const event = this.events.get(name); |
| 11 | + if (event) event.add(fn); |
| 12 | + else this.events.set(name, new Set([fn])); |
| 13 | + } |
| 14 | + |
| 15 | + once(name, fn) { |
| 16 | + const wrapper = (...args) => { |
| 17 | + this.remove(name, wrapper); |
| 18 | + fn(...args); |
| 19 | + }; |
| 20 | + this.wrappers.set(fn, wrapper); |
| 21 | + this.on(name, wrapper); |
| 22 | + } |
| 23 | + |
| 24 | + async emit(name, ...args) { |
| 25 | + const event = this.events.get(name); |
| 26 | + if (!event) return; |
| 27 | + const promises = [...event.values()].map(fn => fn(...args)); |
| 28 | + return Promise.all(promises); |
| 29 | + } |
| 30 | + |
| 31 | + remove(name, fn) { |
| 32 | + const event = this.events.get(name); |
| 33 | + if (!event) return; |
| 34 | + if (event.has(fn)) { |
| 35 | + event.delete(fn); |
| 36 | + return; |
| 37 | + } |
| 38 | + const wrapper = this.wrappers.get(fn); |
| 39 | + if (wrapper) { |
| 40 | + event.delete(wrapper); |
| 41 | + if (event.size === 0) this.events.delete(name); |
| 42 | + } |
| 43 | + } |
| 44 | + |
| 45 | + clear(name) { |
| 46 | + if (name) this.events.delete(name); |
| 47 | + else this.events.clear(); |
| 48 | + } |
| 49 | + |
| 50 | + count(name) { |
| 51 | + const event = this.events.get(name); |
| 52 | + return event ? event.size : 0; |
| 53 | + } |
| 54 | + |
| 55 | + listeners(name) { |
| 56 | + const event = this.events.get(name); |
| 57 | + return new Set(event); |
| 58 | + } |
| 59 | + |
| 60 | + names() { |
| 61 | + return [...this.events.keys()]; |
| 62 | + } |
| 63 | +} |
| 64 | + |
| 65 | +// Usage |
| 66 | + |
| 67 | +const ee = new AsyncEventEmitter(); |
| 68 | + |
| 69 | +(async () => { |
| 70 | + |
| 71 | + ee.on('e1', async () => { |
| 72 | + console.log('e1 listener 1'); |
| 73 | + }); |
| 74 | + |
| 75 | + ee.on('e1', async () => { |
| 76 | + console.log('e1 listener 2'); |
| 77 | + }); |
| 78 | + |
| 79 | + ee.on('e1', async () => { |
| 80 | + console.log('e1 listener 3'); |
| 81 | + }); |
| 82 | + |
| 83 | + ee.on('e2', async () => { |
| 84 | + console.log('e2 listener 1'); |
| 85 | + }); |
| 86 | + |
| 87 | + ee.on('e2', async () => { |
| 88 | + console.log('e2 listener 2'); |
| 89 | + }); |
| 90 | + |
| 91 | + console.log('begin'); |
| 92 | + await ee.emit('e1'); |
| 93 | + await ee.emit('e2'); |
| 94 | + console.log('end'); |
| 95 | + |
| 96 | +})(); |
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